Structures of the Ratibidanolides, Sesquiterpene Lactones with a New Carbon Skeleton, and Unusual Xanthanolides from Ratibida columnifera

Article abstract of DOI:10.1021/jo00205a012

Structures and stereochemistry of two sesquiterpene lactones from Ratibida columnifera which possess a new rearranged eudesmane derived carbon skeleton were deduced by NMR spectroscopy and X-ray diffraction.The main lactone fraction of this plant consisted of a family of unusual xanthanolides whose structures were established in the same manner.Other constituents included the new nerolidol derivative (3S^*,5R^*)-(-)-5-hydroxy-9-oxonerolidol.